Reference may be made to our U.S. Pat. Nos. 5,466,187 and 6,669,551, assigned to Jack Kennedy Metal Products & Buildings, Inc. of Taylorville, Ill., for background on mine ventilation structures (e.g., overcasts and undercasts). Reference may also be made to the book titled “Practical Mine Ventilation” by William R. Kennedy, published in 1996 and 1999 by Intertec Publishing Corporation, for background on mine ventilation structures in general. The aforementioned patents and book are incorporated herein by reference.
The mine ventilation structures referred to in our U.S. Pat. Nos. 5,466,187 and 6,669,551 are fabricated from elongate deck panels of inverted channel shape in transverse cross section, each panel having a top formed by a web, opposite sides extending down from the web, and in-turned flanges at lower ends of the sides. The deck panels are placed alongside one another to form a deck for the ventilation structure. Achieving a tight fit between the sides of adjacent deck panels is difficult, often resulting in small gaps between adjacent panels through which air can escape, which is undesirable. There is a need, therefore, for an improved construction which eliminates this problem.